TLV340X BURR-BROWN [Burr-Brown Corporation], TLV340X Datasheet - Page 8

• Manufacturer Part Number: TLV340X
• Description: Nanopower, 1.8V, SOT23 Comparator with Voltage Reference
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

APPLICATIONS INFORMATION
The TLV3011 is a low-power, open-drain comparator with
on-chip 1.242V series reference. The open-drain output
allows multiple devices to be driven by a single pull-up
resistor to accomplish an OR function, making the TLV3011
useful for logic applications.
The TLV3012 comparator with on-chip 1.242V series refer-
ence has a push-pull output stage optimal for reduced power
budget applications and features no shoot-through current.
A typical supply current of 2.8 A and tiny packaging combine
with 1.8V supply requirements to make the TLV3011 and
TLV3012 optimal for battery and portable designs.
BOARD LAYOUT
Typical connections for the TLV3011 and TLV3012 are
shown in Figure 1. The TLV3011 is an open-drain output
device. A pull-up resistor must be connected between the
comparator output and supply to enable operation.
To minimize supply noise, power supplies should be capaci-
tively decoupled by a 0.01 F ceramic capacitor in parallel
with a 10 F electrolytic capacitor. Comparators are sensitive
to input noise, and precautions such as proper grounding
(use of ground plane), supply bypassing, and guarding of
high-impedance nodes will minimize the effects of noise and
help to ensure specified performance.
FIGURE 1. Basic Connections of the TLV3011 and TLV3012.
OPEN-DRAIN OUTPUT (TLV3011)
The open-drain output of the TLV3011 is useful in logic
applications. The value of the pull-up resistor and supply
voltage used will affect current consumption due to additional
current drawn when the output is in a low state. This effect
can be seen in the typical curve Quiescent Current vs Output
Switching Frequency .
EXTERNAL HYSTERESIS
Comparator inputs have no noise immunity within the range
of specified offset voltage ( 12mV). For noisy input signals,
the comparator output may display multiple switching as
input signals move through the switching threshold. The
typical comparator threshold of the TLV3011 and TLV3012 is
threshold of the TLV3011 or TLV3012, external hysteresis
8
V
0.5mV. To prevent multiple switching within the comparator
IN–
V
IN+
4
3
TLV301x
5
REF
V+
6
2
V–
1
NOTE: (1) Use R
0.01 F
10 F
PULL-UP
R
10k
with the TLV3011 only.
PULL-UP
(1)
V
OUT
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FIGURE 3. TLV3011 Configured as a Low Battery Level Detector.
may be added by connecting a small amount of feedback to
the positive input. Figure 2 shows a typical topology used to
introduce hysteresis, described by the equation:
FIGURE 2. Adding Hysteresis.
V
switch the comparator output by increasing the threshold
region, thereby reducing sensitivity to noise.
APPLICATIONS
BATTERY LEVEL DETECT
The low power consumption and 1.8V supply voltage of the
TLV3011 make it an excellent candidate for battery-powered
applications. Figure 3 shows the TLV3011 configured as a
low battery level detector for a 3V battery.
HYST
V
NOTE: (1) Use R
When the battery voltage drops below 1.9V,
the battery-okay output will go low.
IN
+
will set the value of the transition voltage required to
V
REF
Battery Okay Trip Voltage
R
39k
1
REF
TLV301x
PULL-UP
R
2M
R
1M
V+
560k
2
1
R
NOTE: (1) Use R
V
5.0V
2
V
HYST
with the TLV3011 only.
HYST
= 0.38V
1.242V
R
PULL-UP
V
R
V
1
OUT
PULL-UP
TLV3011, TLV3012
(1)
R
R
2
1
TLV301x
1 242
.
with the TLV3011 only.
REF
SBOS300B
R
1
R
2
R
R
2
PULL-UP
Battery
Okay
(1)